1. Field of the Invention
The present invention relates to a heat radiator for radiating heat of electronic parts (heat generating elements) that radiates heat by electric supply, typically, such as a semiconductor parts mounted on a circuit board surface of a printed circuit board.
2. Description of the Prior Art
For instance, a conventional radiator is well known in which, as shown in FIG. 19, a sleeve member 52 formed and bent into a bellows is fixed to a back surface plate 51 made of aluminum alloy and a heat generating element a is mounted below the sleeve member 52. Bracket-like leg seats 54 provided with leg pins 55 for insert-fitting to a circuit board are mounted on both lower sides of the above-described heat generating element a.
Rail-like projections 53 extending in the lateral way are formed on an upper side of the surface of the back surface plate 51 for mounting the sleeve member 52 on the back surface plate 51. Then, press-fitting slits 50 for engagement with the above-described projections 53 are formed in a base end portion of the sleeve member 52. The sleeve member 52 is fixed to the back surface plate 51 by press-fitting the projecting surfaces of the projections 53.
Also, with respect to the leg seat 54, pin holes 57 formed in a side of each leg seat 54 hating an L-shaped cross-section are fitted with rivets 56 projecting from the surface by being pressed from the back surface of the back surface plate 51. The projecting end of each pin (rivet) 56 is press-fitted to be fixed to the back surface plate 51 in a one-piece manner. Reference numeral 58 denotes a positioning pin for the leg seat 54.
The conventional radiator having the above-described structure radiates heat of the lower heat generating element a mainly by the upstream flow of air within the sleeve member 52. However, since the back surface plate 51 and the sleeve member 52 are formed separately, the conventional radiator suffers from such various disadvantages that the press-fitting work is performed in an independent step after the back surface plate 51 and the sleeve member 52 are formed separately; the press-fitting portions have to be formed in the back surface plate 51; and the thickness has to be increased, thereby increasing in cost for production.
In addition, a volume of the overall radiator is disadvantageously increased, resulting in degraded heat radiation.